Microsoft employees protested the company's $480 million contract to supply the US Army with augmented-reality headsets in a letter in which they say they "did not sign up to develop weapons."

The technology giant was awarded the so-called Integrated Visual Augmentation System (IVAS) contract with the US Department of the Army in November. Under the terms of the contract, Microsoft is to "rapidly develop, test, and manufacture a single platform that Soldiers can use to Fight, Rehearse, and Train that provides increased lethality, mobility, and situational awareness necessary to overmatch against out current and future adversaries."

For the signatories of the letter, updating the HoloLens device to fulfill the contract, would see the technology giant cross the line "into weapons development."

HoloLens, Microsoft's augmented reality headset, was first released in 2016. It allows the wearer to add digital content over the real world. CEO Satya Nadella is expected to unveil the HoloLens 2 at the Mobile World Congress on Sunday in Barcelona.

"We did not sign up to develop weapons, and we demand a say in how our work is used," the employees wrote, adding: "Intent to harm is not an acceptable use of our technology."

Instead, they call on Nadella and president and chief legal officer Brad Smith to cancel the IVAS contract, cease to develop any and all weapons technology and appoint an independent, external ethics review board with the power to enforce any publicly validated compliance with this policy.

The letter follows an October 2018 blog post by anonymous Microsoft employees released on Medium in which they demanded the company withdraw its bid for a $10 billion Joint Enterprise Defense Infrastructure contract with the Department of Defense.

At the time, the company responded with its own blog post in which it said it didn't "ask or expect everyone who works a Microsoft to support every decision the company takes" and that any employee uncomfortable working on a project could ask to be affected to a different one.

But employees rejected that proposal in their latest letter.

"There are many engineers who contributed to HoloLens before this contract even existed, believing it would be used to help architects and engineers build buildings and cars, to help teach people how to perform surgery or play the piano, to push the boundaries of gaming, and to connect with the Mars Rover (RIP)."

"These engineers have now lost the ability to make decisions about what they work on, instead finding themselves implicated as war profiteers," they wrote.

Contacted by Euronews, a Microsoft spokesperson said: “We gave this issue careful consideration and outlined our perspective in an October 2018 blog. We always appreciate feedback from employees. As we said [in October], we’re committed to providing our technology to the U.S. Department of Defense, which includes the U.S. Army under this contract. We’ll remain engaged as an active corporate citizen in addressing the important ethical and public policy issues relating to AI and the military.”